The present invention relates generally to suspension systems for vehicular or muffler exhaust systems and processes for producing hanger means for use in such suspension systems.
The muffler and exhaust pipe elements of a vehicular exhaust system have generally been suspended beneath the vehicular frame by suspension devices designed to isolate the vibration and thermal characteristics of these exhaust system elements from the passenger or cargo compartments of the vehicle. Such isolation permitted smooth thermal expansion of the exhaust pipe, by reducing thermal stress, as well as a quieter and pleasanter ride for passengers. Such suspension devices have generally included a hanger means secured to the exhaust system elements, which has a hooked or curved end portion suitable for connection with a flexible isolator means. The isolator means may have had a passageway through a portion of it into which the hooked end of the hanger means could be inserted. The isolator means may have been secured to the vehicular frame directly or secured indirectly through a separate suspension system element.
The hanger means for such suspension systems have been formed in various ways, including welding together two separate stampings of sheet metal or a shaped wire or rod and a single sheet metal stamping. Although these two hanger designs have performed satisfactorily in exhaust suspension systems, they are subject to several problems typically experienced in welded assemblies, including stress corrosion, incomplete welding, and localized softening. Another disadvantage of such hanger means has been that the numerous and time consuming production steps of stamping, assembling, and welding substantially increase hanger cost. Also, welding production processes have often confronted problems removing from the production environment the excess heat generated by welding.
Although various other hanger means have been employed in such suspension systems which have not had all the disadvantages of these welded assemblies, it has been difficult to efficiently produce an inexpensive hanger means which provides for secure connection with the isolator means without substantially increasing the difficulty of insertion and connection, causing excessive wear and tear on the isolator means, or increasing significantly the overall weight of the suspension system and, thus, decreasing vehicle fuel efficiency.